Is variable speed REALLY that great?

AlphaMoose said:
I gotta say though. It really makes me mad how KMG just WONT sell a product you can use right away. I mean, the 3 speed is bad enough but at least you can get the package of everything you need to wire it. The VS just says "Obtain a 14/3 cord". Like, excuse me, this is a $2k tool. How about you SUPPLY that.
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unless you want to mess with drive belts and pulleys, find something other than a KMG. Pheer, Wilmont, Polar Forge and others sell grinders designed for direct drive. all of them will sell you a grinder that is "plug and play", but they charge you dearly. basic wiring for VFD/3 phase is only 7 wires.
 
The polar bear forge kit is pretty good. Use good taps. I'm not sure what steel he is using but my import taps simply weren't up to the job.
 
Our esteem is a very good grinder. 2hp direct drive with VFD..I never knew what I was missing and I had about the nicest multi speed pulley setup you can have
Heres the set up we use on our coote..It works very well...
Our Coote isnt designed for more than 2000 rpm's so using step pulleys back to back would be wasted because we couldent use one of the pulleys due to the speed being way to fast..So we made this mounting bracket that lets you use one step pulley and move the motor.The motor mount slides on a piece of 16ga 3/4" tubing which fits perfectly on 5/8" round. Two stops made from the same with thumb screws at either end to stop the motor from drifting while running. One acts as a gauge as the shaft is marked in all 4 spots corresponding to the pulley changes.Just move the stop to the corresponding mark and tighten it.then slide the motor over.Takes about 6-7 seconds to change speeds..The step pulley is 4"-3 1/2"-2 1/2"-2"..The pulley on the grinder is 4".The motor is 1725rpm's, 1 1/2 H.P.This gives us..
1725 RPM's
1509 RPM's
1078 RPM's
862 RPM's
.
Not a VFD but better than single speed and no wasted pulleys..

newpics538.jpg

Heres the bracket before mounting and clean-up.
newpics539.jpg

After mounting. before final clean-up and painting..
 
Yes variable speed is great. Especially for fine details in grinding, think plunge areas, clips, etc. And it excels on handle and guard work. Someone told me a long time ago, don't skimp on your machinery, you will only regret it down the line.
Brion
 
Hey everybody. Not a knife maker here but I was wondering if there is any reason you couldn't just use a router variable speed controller to adjust your rpms. They run about $20 bucks and you can make a motor run at any speed from zero to full. I use them for lots of things. Got one hooked to my Worksharp and really like being able to adjust the speed.
 
quartertime said:
Hey everybody. Not a knife maker here but I was wondering if there is any reason you couldn't just use a router variable speed controller to adjust your rpms. They run about $20 bucks and you can make a motor run at any speed from zero to full. I use them for lots of things. Got one hooked to my Worksharp and really like being able to adjust the speed.
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That works on low powered universal motors with brushes.


It will not work on proper motors used on grinders


No one would pay hundreds for a VFD if a $20 router controller would do.
 
[video=youtube;C5ZMEHY6QtM]https://www.youtube.com/watch?v=C5ZMEHY6QtM[/video]
JG Custom Metal Works said:
Huh? Most VFDs have a port that can utilize a reverse switch. You don't have to reverse the belt. I have never reversed the belt on mine and have used the reverse function a ton. It's real handy when sharpening.

I think you'll be happy with going with the VFD. It's worth it. If I had to do it over again I might consider another grinder over the KMG. I love my KMG but I'm really a fan of the direct drive. I get a lot of wobble with mine and the tracking isn't as great as I've seen with other machines. I can level it out by adjusting it but it's just kind of a PITA. I'd probably look at the Northernridge Tool 2x72 or possibly the Pheer. Of course the TW-90 but that is pretty dang pricey.
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JG, You may to try to install a gas piston for tension on your KMG and buy a 4 inch tracking (idler wheel) wheel from Jackstraw on Ebay. These two things smoothed out my KMG . I use a 40 pound gas piston. My Kmg now runs smooth and with little vibration. I also have a direct drive grinder that is smooth an quiet but I prefer to work with my KMG. Just my opinion. Larry P.S. The first photo here shows the grinder with a stock tracking wheel and not the new 4 inch tracking wheel. LL
ghDPcl6m.jpg
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JG Custom Metal Works said:
I'm talking about the belt too, which I mentioned in the post you quoted. I'm not sure what that guy told you but I've never had a problem with having to reverse a belt.
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Most belts can be run in either direction without problems, but some are spliced in a way that can cause lumpy operation or failure. If you have never had a belt explode, that's great, but it happens.
 
I started on the HF 1x30 and now I have two variable speed grinders. The first one i was going to be cheap but then after reading enough about what others did and thinking about how much i hated switching pulley's on my drill press i opted to spend the extra $200 on a VFD. I could not imagine having gone pulley's. It is one thing you'll never regret, its half a second to change the speed and it can be made forward/reverse. I would only reply to this thread at this point to help influence other people when the get to the same point you are at. The main point in this thread: We've all been there at the point of deciding to save a little more or jump the gun and get the pulley's to start making knives. Most of these guys are who influenced my decision to get a VFD.
 
Another option is to look at another grinder than a KMG--I have a NorthRidge Tools grinder, and an AMK http://amktactical.com/epages/3c926...26a50-9aba-43a5-9571-098ee03f1288/Products/42 In looking this variable speed NEMA 4 VFD, is only about $200 over the 3 speed pulley system KMG--the AMK also has a vertical/horizontal flip option, and a 12" contact wheel. I feel this is a much better value than a KMG--just something to consider! ;)
 
Fwiw, lacking a "reverse port", on a VFD, any 3ø motor can run in reverse by reversing any 2 of its power leads.
Just be sure the motor is at dead stop before throwing a reverse switch.

Variable speed is a treat. "Buy once, cry once". Do it !!
Also, if at all possible, run you VFD on 240 volt.
 
Fish30114 said:
Another option is to look at another grinder than a KMG--I have a NorthRidge Tools grinder, and an AMK http://amktactical.com/epages/3c926...26a50-9aba-43a5-9571-098ee03f1288/Products/42 In looking this variable speed NEMA 4 VFD, is only about $200 over the 3 speed pulley system KMG--the AMK also has a vertical/horizontal flip option, and a 12" contact wheel. I feel this is a much better value than a KMG--just something to consider! ;)
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How do you like that Northridge? I think your the only one I've seen that actually owns one. They definitely look sweet and price is about the same as Brett's Esteem
 
How is that Northridge? Im pretty set on the Pheer after hearing from Jose but the NR is tempting, particulary because it would arrive much faster. Still, I like Jose and his support seems great.
 
I actually love my North Ridge. I bought the version they dub the 'pro series' it came with a small wheel attachment and the horizontal flip stand. I can tell you one thing for certain, it is made very precisely, it runs super smooth. I also upgraded to a 2.5 HP Baldor motor on mine. The work table is very nice, specifically the adjustments of it. I have spoken a lot to the owner of North Ridge, and am impressed with their commitment to having the best components for their grinder. Several items within the grinder did not have a high enough quality piece available in the marketplace, so they made them theirselves--very strong commitment to high quality. I would recommend it over the KMG, Pheer, Wilmont, and The Uber-grinder--all of which I have experience with.

All in all, I highly recommend their machine!
 
VFD is absolutely worth the money . So is buying a quality grinder with parts you can get . I am not keen on buying from new kids when it comes to my equipment . I use a KMG it's super heavy it can also be converted to direct drive . You can get trees to store your tooling arms Etc . I have used several grinders before so I do have experience with other units . They may not be flashy but they are industrial made and I doubt you you would need another .
 
CAN you make knives without variable speed?

Sure.

There's plenty of guys that ride one speed bikes with no brakes, too.

If the thought of infinitely variable speed control to cater to the application doesn't make sense to an individual, I'm not sure any amount of discussion will convince someone.

To state it from my OWN perspective, purchasing a machine without variable speed is tantamount to taking a dump before pulling your trousers down.

Everyone is entitled to their own opinion.

;)
 
I started on a 2hp three speed kmg. For a second grinder, I eventually built a Little Buddy and installed a 3hp (3600rpm) motor, direct drive, 6 inch drive wheel and variable speed. It is great to have but I still do 95% of my grinding on high or medium speed on the kmg.
 
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